Extrusion as an element of resource and energy saving technologies for processing of underutilised cartilage fish of the Northern Basin

Currently one of the main objectives of the domestic fishery complex development is to increase the efficiency of aquatic biological resources (ABR) extraction and optimize their processing. Accelerating rate of ABR processing is associated with the search and implementation of energy-saving, low-waste and waste-free technologies to increase the number and expand the diversity of feed and food products. Starry ray (Raja radiata) is valuable raw material containing significant amount of high-quality protein, as well as a number of important trace elements for nutrition, such as cobalt, nickel, fluorine, chromium, copper, iodine, iron, sulfur, chlorine, phosphorus, potassium, magnesium, sodium, vitamin PP and others. High content of chondroitin sulfate in starry ray meat makes it an indispensable component of functional nutrition, as well as in the production of special feeds. The study of grinding process of frozen raw material from starry ray on a piston-type extrusion unit with cooled working bodies allowed to determine rational grinding regimes with the lowest possible energy costs. The subsequent organoleptic evaluation of the obtained minced meat confirmed that the product has homogeneous structure and crumbly, juicy texture. In order to establish the shelf life of the semi-finished product produced, standard tests were carried out to determine the quality and safety parameters during its storage. To do this, organoleptic indicators were monitored, and the dynamics of fluctuations of nitrogen content of volatile bases being the indicator of the prevailing type of damage to this product. The determination of nitrogen in volatile bases was carried out using titrimetry. The results of the study can be used in the development of feed mixtures.